English Reference
noun

DAC

n.
US /ˈdæk/ dac

  1. 01 C1 Advanced Technical Computing

    Stands for Digital-to-Analog Converter. A piece of technology that turns digital files into sound you can hear.

    Abbreviation for Digital-to-Analog Converter. A hardware component that translates binary data into an analog signal for reproduction through speakers or headphones.

    Simple

    He bought an external DAC to get better sound quality from his computer.

    In context

    Audiophiles often invest in high-end external DACs to bypass the inferior integrated sound chips found in standard consumer laptops.

    Usage

    Usually functions as a countable noun referring to the physical device.

    Teacher's tip

    In modern consumer electronics, this is the most common sense a learner will encounter, especially in discussions about high-fidelity audio.

    ADC
  2. 02 C2 Proficiency TechnicalAcademic Science

    Stands for Direct Air Capture. A technology that pulls carbon dioxide directly out of the air to help the environment.

    Abbreviation for Direct Air Capture. A process of capturing carbon dioxide directly from the ambient air using chemical reactions.

    Simple

    Scientists are building a new DAC plant to help reduce greenhouse gases.

    In context

    The viability of DAC as a climate solution depends heavily on the availability of cheap renewable energy to power the carbon extraction process.

    Usage

    Often used as an uncountable noun or as a modifier before another noun.

    Teacher's tip

    This is a relatively new term in environmental science and is frequently seen in news reports about climate change technology.

    carbon capture
  3. 03 C2 Proficiency British EnglishFormal Law

    Stands for Deputy Assistant Commissioner. A very high-ranking officer in the London police.

    Abbreviation for Deputy Assistant Commissioner. A senior rank within the Metropolitan Police Service in London, sitting above Commander.

    Simple

    The DAC held a press conference to discuss the major investigation.

    In context

    As a DAC in the Metropolitan Police, she was responsible for overseeing specialist operations across the entire city.

    Usage

    Used as a title or a countable noun within the context of UK law enforcement.

    Teacher's tip

    This sense is highly specific to the UK and is rarely used outside of discussions involving the London Metropolitan Police.

They also plan to investigate its use with CO₂ recovered directly from the atmosphere through direct air capture (DAC) technologies.

Phys.org· 7 Sept 2026
This entry
Level C1 · Advanced
Frequency Occasional
Updated